Pesticide uses in Thailand can cause several adverse effects such as economy, environmental and health effects. Cross sectional study aimed to study (1) physical, mental and social health impacts from pesticide uses, (2) occupational knowledge and practice, and (3) association between health symptoms and laboratory results among 51 garlic farmers from Mae Na Reur Subdistrict, Muang District, Phayao Province. Questionnaire and laboratory analysis (dialkylphosphate metabolites, acytylcholinesterase activity and DNA damage) were used. The results have shown that (1) physical health: important symptoms associated with pesticide uses were headache, dizziness, numbness, red/white rash and red/white pimple; average of dialkylphosphate metabolites 10.9±8.5 mg/kg creatinine, average of acytylcholinesterase activity 10,273±1,353 U/L, average of tail length and tail moment 6.2±0.7 and 3.2±0.3 mm, respectively; (2) mental health: farmers worried that pesticides had an effect on themselves (90.2%), consumers (88.2%), and their descendant (88.2%); (3) social health: farmers planted another crops with pesticide free for eating (90.2%), needed to employ pesticide sprayers (56.9%), and competed with neighbors for planting (23.5%); (4) most farmers had high occupational knowledge and practice, but some farmers did not use gloves and mask during pesticide uses; and (5) health symptoms related with laboratory results were dizziness, red/white rash, red/white pimple, and chest pain. Therefore, promotion of safety agricultural system in order to change the attitude of farmers can lead to solve health problem of farmers.